Clauses

You'll have to use clauses if you want a higher IELTS band.

But I have found that even advanced-level students have trouble using clauses, which they seem to find so difficult to put into sentences naturally.

Subject and Object Relative Pronouns

Relative pronouns are: that, who, whom, whose, which, where, when, and why. They are used to join clauses to make a complex sentence.

Common Examples

Last weekend I went to Yang Min Mountain. It's a beautiful place near Taipei
Last weekend I went to Yang Min Mountain, which is a beautiful place near Taipei

I live with a girl. She used to be my classmate.
I live with a girl who used to be my classmate.

So use clauses to connect two simple sentences or clauses. That has to become a habit, and your teacher should be hitting you every time you don't do it, haha. I know the first example there is kind of Chinese English: something to be aware of.

Subject

I like guys who aren't too serious.
I like guys who have a good sense of humour.

The subject relative pronoun cannot be omitted -- you need it.

Object

I'd prefer someone (whom/who/that) I can talk to easily.
I'd prefer someone (whom/who/that) I can have fun with.

whom is grammatically correct. who is much more common. that is correct, but doesn't sound right. The object relative pronoun can be omitted. But I think it's better to keep it there, just to show that you know about it.

So don't worry about identifying which is object and which is subject. Just get into the habit of always using the clause

More Examples

I saw a movie that I really liked the other day.

I don't like movies that have a lot of violence.

I think the person who I talked to on the telephone was the manager.

The apartment that I have been living in is not that nice.

When I went to my high school reunion, I saw people whom I hadn't seen in over twenty years.